From laptop computers and personal digital assistants to multimedia players and mobile phones, a wide variety of electronic devices require power from a power source, and rely on communication between two electronic systems to optimize their operation and collaboration. These electronic devices come with a wide variety of power supplies, sometimes referred to as “wall warts,” “power bricks,” or “power adapters.” Unfortunately, these power supplies are often specific to the device type, device manufacturer, and/or device product line, and are therefore incompatible with each other. If a user loses a power supply for a device, the power supply of another device generally cannot be used as a substitute. This causes many problems. Travel is made more inconvenient by the prospect of having to carry multiple power supplies for various portable devices. A device may be damaged and/or its useful life shortened if the wrong power supply is used. Furthermore, as devices become obsolete and are discarded, the power supplies for the devices may have to be discarded as well because users often do not have other devices that are compatible with these power supplies.
Attempts have been made to resolve the problem associated with incompatible power supplies. In one example, a common power supply hub is used to supply power to different devices or to multiple devices. The power supply hub may have a single port for powering one device at a time, or multiple ports to supply power to multiple devices. In some instances, multiple port power supply hubs may accommodate different types of connectors. In other instances, the supply hubs may accommodate identical connectors.
However, because different devices may have varying power needs, conventional power supplies are unable to accommodate both high and low powered devices effectively. For typical power supply hub architectures, having either a single port or multi-ports, each port is burdened by the cost and size of a power circuit that has the ability to deliver power to the highest powered load device that may be connected. In effect, each port has to be over-designed to meet the highest-power application. For cost-sensitive products, such as power supply hubs, this is not an acceptable approach.
Furthermore, conventional power supplies typically waste power due to inefficient design. For example, due to design limitations, a power supply continues to drain power while it is connected to an AC power source, such as to a wall outlet, even when a load device is not connected to the power supply or when the load device is on a power saving mode. The power supply has to be physically disconnected from the AC power source to save power. Today's load devices typically come with innovative power-saving features. It is undesirable to have a power efficient load device connecting to a power supply that operates inefficiently and wastes power. Thus, power-saving features in the power supply are desired to connect to power efficient load devices.